Enzymes attached to cellulose carbonate

ABSTRACT

CELLULOSE CARBONATE IS PREPARED BY REACTING CELLUSLOSE OR A 6-SUBSTITUTED CELLULOSE, E.G. METHYL CELLULOSE, HYDROXYETHYL CELLULOSE, CARBOXYMETHYL CELLULOSE AND DIETHYLAMINOETHYL WITH AN ALKYL OR ARYL CHLOROFORMATE. WATER-INSOLUBLE ENZYME PREPARATIONS ARE PRODUCED BY REACTING THE ENZYME, E.G. MOUSE KIDNEY EXTRACT. B-GLUCOSIDASE, TRYPSIN. A-AMYLASE, GLUCOMYLASE OR MOUSE LIVER EXTRACT, DISSOLVED OR SUSPENDED IN AQUEOUS SOLUTION WITH THE CELLUSLOSE CARBONATE.

United States Patent M 3,810,821 ENZYMES ATTACHED TO CELLULOSE CARBONATE Sidney Alan Barker, John Frederick Kennedy, and Charles 5 John Gray, Birmingham, England, assignors to Ranks Hovis McDougall Limited, London, England No Drawing. Continuation-impart of applications Ser. No. 95,414, Dec. 4, 1970, now abandoned, and Ser. No. 98,214, Dec. 14, 1970, now Patent No. 3,705,890. This application Dec. 7, 1972, Ser. No. 312,928

Claims priority, application Great Britain, Dec. 18, 1969,

61,701/69, 61,702/69 Int. Cl. C07g 7/02 US. Cl. 195-63 12 Claims ABSTRACT OF THE DISCLOSURE Cellulose carbonate is prepared by reacting cellulose or a 6-substituted cellulose, e. g. methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose and diethylaminoethyl with an alkyl or aryl chloroformate. Water-insoluble enzyme preparations are produced by reacting the enzyme, e.g. mouse kidney extract, fl-glucosidase, trypsin, u-amylase, glucoamylase or mouse liver extract, dissolved or suspended in aqueous solution with the cellulose carbonate.

This application is a continuation-in-part of application S.N. 95,414 filed Dec. 4, 1970, now abandoned, and a continuation-in-part of application S.N. 98,214, filed Dec. 14, 1970, now US. Pat. No. 3,705,890.

The invention is for improvements in or relating to cellulose derivatives and has particular reference to cellulose carbonate.

It is an object of the invention to provide as new chemical compounds cellulose carbonates and methods for their preparation.

A cellulose carbonate prepared as hereinafter described in Examples I to III may be employed inter alia as a solid matrix in chemical coupling with enzymes such as glucosidase and trypsin or mixtures of one or more enzymes as described in our copending application S.N. 95,414, filed Dec. 4, 1970 and hereinafter in order to provide water insolubilized enzyme preparations in a form in which they can be used repeatedly and be more stable to heat than the corresponding soluble enzyme.

The reaction of excess of ethyl chloroformate with pyranoid compounds containing vicinal diequatorial hydroxy groups is known to give trans-five membered cyclic derivatives in the presence of triethylamine. Thus, methyl 4,6-O-benzylidene-a-D-glucopyranoside gave the 2,3-carbonate and methyl 2,6-di-O-methanesulphonyl-a-D-glucopyranoside gave the 3,4-cyclic ester (Doane, W. M., Shasha, B. 5., South, E. I., Russell, C. R. and Rist, C. E., Carbohydrate Res., 4, 445 [1967]). According to reaction conditions methyl 4,6-O-benzylidine-a-D-glucopyranoside also gave the 2,S-di-O-ethyloxycarbonyl or the 2- and B-monoesters. These workers also stated that the 2,3- trans fused cyclic carbonates showed characteristic absorptions in the region of 1825 cm:- and 1840 and 1810 crnr of the infrared spectrum. The O-ethyloxycarbonyl group absorbed at 1750 cmf Carbonate derivatives have been made of polysaccharides such as dextran and dextrin, that are soluble in dimethyl sulphoxide (Doane W. M., South, E. 1., Shasha, B. S. Russell, C. R. and Rist, C. E. Carbohyd. Res. 5, 366 [1967], 8, 266 [1968]). The cellulose carbonate described herein is so far as we are aware the first insoluble polymer converted to its carbonate derivative. 2,3-trans cyclic carbonates undergo ring opening with methanol, toluenethiol or piperidine to give mixtures of the 2- or 3-substituted derivatives in the presence of triethylamine (South, E. I., Doane, W. M., Shasha, B. S.,

Patented May 14, 1974 lose may also be substituted at C in some or all of its l,4-

B-D-glucopyranose units. Thus the cellulose carbonate may contain not only cyclic carbonate structures derived by reaction of ethyl chloroformate with the trans hydroxyl groups on carbon two and carbon three of some or all of the D-gluco-pyranose residues in the cellulose but also O-ethyloxycarbonyl groups derived by the reaction of ethyl chloroformate with certain of the hydroxyl groups on carbon two, three or six of the D-glucopyranose residues.

According to the present invention there is also provided a process for the preparation of a cellulose carbon ate which comprises reacting cellulose or a 6-substituted cellulose with an alkyl or aryl chloroformate in an organic solvent.

The chloroformate is preferably ethyl chloroformate. Methyl chloroformate, phenyl chloroformate and benzyl chloroformate may also be employed.

The reaction may be conveniently carried out at 0 C. for approximately 10 minutes in dimethyl sulphoxide! dioxan. Dimethylformamide/dioxan or other solvent mixture may also be employed.

A base for example a tertiary amine is preferably present.

All components of the reaction are preferably dry.

The ethyl chloroformate and tertiary amine, e.g. triethylamine, may be dissolved in dimethyl sulphoxide or dimethylformamide or other solvent or solvent mixture devoid of 0H, --SH, NH and -NH groups.

The 6-substituted cellulose may be methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose or diethylaminoethyl cellulose. Thus the cellulose employed as starting material may be already substituted at C in some or all of its 1,4-B-D-glucopyranose residues.

The cellulose carbonate products of the present invention may also be employed as intermediates in the preparation of 6-substituted cellulose derivatives with modified solubility properties when derivatives may be more resistant to microbial breakdown.

Following is a description by way of example of methods of carrying the invention into elfect.

EXAMPLE I Cellulose (1 g. Sigmacell type 33 purchased from Sigma Chemical Co., England) was suspended in liquid dimethyl sulphoxide 10 ml.), p-dioxan (1.5 ml.) and triethylamine (8 m1.) and stirred at 0 C. for 5 minutes. Ethyl chloroformate (16 ml.) was added dropwise, and stirring continued for 10 minutes.

The mixture was then neutralized to pH 7.0 with 6 N HCl. The mixture was suspended in ethanol (400 ml.) at 20 C. using a Waring blender, filtered, and the cellulose carbonate washed with 90% ethanol (200 ml.), ethanol (200 ml.) diethyl ether (200 ml.) and dried in vacuo over P 0 at 20 C.

EXAMPLE II Example I was scaled up five times except that proportionally more dimethyl sulphoxide ml.) was used to suspend the cellulose and only 400 ml. diethyl ether for washing the cellulose carbonate.

This sample and a cellulose control were analyzed by quantitative infrared spectral analysis. Samples (1-3 mg.) were accurately weighed and mixed with ground dry potassium bromide (300 mg). After grinding, the ho mogeneous mixture was pressed at 9.5 tons in a die in an evacuated chamber, and the resultant potassium bromide disc, (13 mm. diameter, 0.8375 mm. thick) placed in the sample beam of a Perkin-Elmer Model 21 double beam infrared spectrophotometer with a scanning range of 4000-650 cmr A blank potassium bromide disc was placed in the reference beam, and scanning was carried out in the range 2000l600 cmf The sample showed peaks at 1835, 1810 and 1750 cm.- and, in terms of a calibration curve constructed from a sample of dextran carbonate containing a known proportion of cyclic carbonate groups assessed by an independent method, the sample contained cyclic carbonate groups on 12.4% of the sugar units (Table I). Subsequent preparations were analyzed by infrared spectroscopy in the same way.

Absorption at 1810 cm.- has been attributed to cyclic carbonate formation while absorption at 1750 cm." has been assigned to ethyloxycarbonyl groups.

EXAMPLE III 7 Example II was scaled up four times (20 g., cellulose) using only 90% ethanol (1.5 1.), ethanol (21.) and diethyl ether (0.5 l.) for washing the cellulose carbonate.

EXAMPLE IV Infrared absorption at- Product lrom- 1,835 cm. 1,810 cm. 1,750 cm.

Methyl chloroformate, 0.95 g---- Absent.-- Absent Present. Ethyl chloroformate, 0.80 g. Present- Present- Do. Phenyl chloroformate, 0.96 g do do Do.

Repetition of the above procedures omitting dimethyl sulphoxide entirely and using p-dioxan (30 ml.) gave products whose infrared spectra showed little or no absorption at 1835, 1810 or 1750 C111. 1, whether derived from methyl, ethyl or phenyl chloroformate. A similar experiment with benzyl chloroformate (24 ml.) gave a similar result.

EXAMPLE V Cellulose (0.2 g., type as used in Example I), dried in vacuo over phosphorus pentoxide at 20 C. for 24 hours, was suspended in dimethyl sulphoxide which had been dried with calcium hydride and distilled under reduced pressure, B.P. 37 C. at 0.5 mm. Hg, (2.0 ml.). p-Dioxan, dried by refluxing for 12 hours with molten sodium and distilled, (0.3 ml.), and triethylamine, dried by treating with potassium hydroxide pellets for 24 hours and distilled, (1.6 ml.) were added and the mixture stirred at C. in an ice bath for minutes. Ethyl chloroformate (3.2 ml.) was added dropwise over 12 minutes,

and the mixture left to react with stirring for 10 minutes.

The mixture was then neutralized to pH 7.0 by the addition of 6.0 N hydrochloric acid. The mixture was washed by stirring and centrifuging with ethanol (9X 15 ml.), diethyl ether (3X 15 ml.) at 20 C, and then dried in vacuo over phosphorus pentoxide at 20 C.

EXAMPLE VI 4 immediately washed .by stirring and centrifuging with pdioxan, which had been dried as in Example V (10X 15 ml.). The first stirring and centrifuging were standardised to effect termination of the reaction within 1 minute. After these washings, the supernatant p-dioxan diluted 1:1 with water showed a pH of 7.5. Washing was continued with ethanol which had been dried over calcium oxide for 24 hours and distilled (3 X 15 ml.), and then continued with diethyl ether, which had been dried over sodium wire (3 X 15 ml.), at 20 C. and the products dried and stored as in Example V.

EXAMPLE VII Cellulose (5 0.2 g.) was reacted with ethyl chloroformate exactly as described in Example VI, using only the 10 minute reaction time but varying the amount of dimethyl sulphoxide (2.0, 1.5, 1.0, 0.5 and 0.0 ml.). In each case where less than the standard amount (2.0 ml.) of dimethyl sulphoxide was used, extra p-dioxan (0.5, 1.0, 1.5 and 2.0 ml., respectively) was used to maintain the concentration of the other reagents. After the reaction, washing and storage were effected as described in Example VI.

EXAMPLE VIII Cellulose (4X 0.2 g.) was reacted with ethyl chloroformate as described in Example VI, using only the 10- minute reaction time but varying the amount of triethylamine (1.6, 0.8, 0.4 and 0.0 ml.). In each case where less than the standard amount (1.6 ml.) of triethylamine was used, extra p-dioxan (0.8, 1.2 and 1.6 ml., respectively) was used to maintain the concentration of the other reagents. After the reaction, washing and storage were effected as described in Example VI.

EXAMPLE IX Cellulose (0.2 g.) was suspended as described in Example VI, but using, in place of dimethyl sulphoxide, dimethylformamide which had been dried over potassium hydroxide then calcium oxide and distilled (2.0 ml.). The reaction with ethyl chloroformate was allowed to proceed for 10 minutes. Washing and storage were effected as described in Example VI.

EXAMPLE X Cellulose (0.2 g.) was treated exactly as described in Example IX. A second lot (0.2 g.) was similarly treated but using less dimethylformamide (1.0 ml.) and additional p-dioxan (1.3 ml. total).

EXAMPLE XI Cellulose (0.2 g.) was treated exactly as described in Example IX. A second lot (0.2 g.) was similarly treated but omitting the use of p-dioxan and using additional dimethylformamide (4.0 ml. total).

EXAMPLE XII Cellulose (0.2 g.) was treated exactly as described in Example IX. A second lot (0.2 g.) Was similarly treated, but omitting the use of triethylamine and replacing it with additional dry p-dioxan (1.9 ml. total).

EXAMPLE XIII Cellulose (0.2 g.) was treated as described in the second experiment in Example XI. A second lot of cellulose (0.2 g.) was similarly treated, but the ethyl chloroformate was added dropwise over 3 minutes instead of over 12 minutes. A reaction time of 10 minutes was used.

EXAMPLE XIV Dry solvents, dry washing, other chloroformates in place of ethyl chloroformate. Cellulose (3X 0.2 g.) was treated as described in Example VI but using equivalent molar quantities of methyl, phenyl and benzyl chloroformates (3.2 ml., 4.5 ml. and 5.0 ml. respectively) in 6 place of ethyl chloroforrnate. Washing and storage were The ring opening reactions of ammonia and benzylefiected as in Example VI. amine to give urethane links further demonstrate the ini- EXAMPLE XV tial presence. of the trans 2,3 cyclic carbonate. 1

This invention is also for improvements in or relatin Diethylaminoethyl cellulose (Type DE 32, Whatman, 5 to enzymes and has particular reference to the modifica- 0.2 g.) was reacted with ethyl chloroformate as described tion of enzymes by attachment to solid matrices.

in ExampleVI using the -minute reaction time. After More particularly, this invention relates to the water the reaction, washing and storage were effected as deinsolubilization of enzymes by chemically attaching them scribed in Example VI. to a cellulose derivative and has as an object the provision TABLE I. QUANTITATIVE INFRARED SPECTROSCOPY OF CELLULOSE CARBONATES Relative height Absorbancy at of cyclic carl,7 50 cm.' (due bonate (1,810 to ethyloxy carcmr peak) with bonyl) relative Optical density per mg. at the maxima of the respect to that to absorbency peaks occurring at the following frequencies-- in Example II at 1 810 ems- (1,810 cm. (cyciic carbon- Example Description of preparation I 1,835 crn." 1,810 cmr 1,75 cm: 1,675 cm: peak) ate) II Wet solvents, larger scale, neutralized before wet 0. 0501 0. 0944 0. 0679 0. 0000 1. 00 0. 72

washing.

V Dry solvents, neutralized before wet washing 0.1551 0.1833 1 0. 1766 0.0000 11 95 0. 96

VI Dry solvents, dry washing- 10 minutes reaction time 0.3409 0. 4122 0. 1476 0. 0685 4 37 0. 36

minutes reaction time- 0. 1525 0. 2139 0. 1698 0. 0000 2 26 1. 79

60 minutes reatcion time. 0. 0912 0. 1102 0. 1188 0. 0000 1 0. 93

240 minutes reaction time 0. 0848 0. 1150 0. 1015 0. 0000 1 21 0. 89

VII Dry solvents, dry washing- 0.75 standard amount DMSO 0. 2041 0.2009 0. 2255 0. 0130 2'. 13 1, 12

0.50 standard amount DMSO. 0. 1380 0. 1686 0. 1065 0. 0181 1. 78 0. 63

0.25 standard amount DMSO. 0. 0600 0. 0646 0. 0286 0.0177 0. 68 0. 44

0.00 standard amount DMSO 0. 0322 0. 0404 0. 0107 0. 0158 0. 43 0. 26

VIII Dry solvents, dry washing- 1.00 standard amount TEA 0. 3630 0.3969 0. 2055 0. 0636 4. 20 0. 52

0.50 standard amount TEA- 0. 0660 0. 1288 0. 0999 0. 0132 1. 39 0. 78

0 25 standard amount TEA- 0. 0014 0. 0039 0. 0015 0. 0106 0. 04 0. 38

0.00 standard amount TEA 0.0000 0. 0018 0. 0020 0.0108 0. 02 1, 48

IX Dry solvents, dry washing- DMF (2 ml.) in place of DMSO 0. 1296 0. 1509 0. 0300 0.0313 11. 0. 20

X Dry solvents, dry washing DMF (2 ml.) in place of DMSO 0. 1106 0. 1400 0.0316 0.0439 1. 48 0. 23

DMF (1 ml.) plus PD (1 ml.) in place of DMS 0. 0868 0. 1057 0. 0349 0. 0288 ll. 12 0. 33

XI- Dry solvents, dry washing- DMF (2 ml.) in place of DMSO 0. 1525 0. 1577 0. 0444 0. 0447 ll. 67 0. 28

DMF (4 ml.) in place of DMSO and PD. 0. 1371 0. 1788 0. 0394 0. 0476 1. 89 0. 22

XII Dry solvents, dry washing- DMF (2 ml.) in place of DMSO 0. 1525 0. 1577 0. 0444 0. 0447 1. 67 0. 28

DMF (2 ml.) in place of DMSO, PD (1.6 ml.) in 0. 0027 0. 0115 0. 0000 0.0240 0. 12 0. 00

place of TEA.

XIII- Dry solvents, dry washing- DMF (4 ml.) in place of DMSO and PD b 0. 1371 0. 1788 0. 0394 0. 0476 l 89 0. 22

XIV Dry solvents, dry washing- BGF (5.0 ml.) in place of ECF 0. 1021 0. 0276 0. 0082 0.0000 0. 29 0.30

MOE (3.2 ml.) in place of ECF- 0.0530 0.0852 0. 0537 0. 0049 0.90 0. 63

PCF (4.5 ml) in place of ECF 0. 0092 0. 0157 0. 0318 0. 0000 0 17 2. 03

Cellulose control 0.0000 0. 0000 0.0000 0. 0000 XV Diethylemioethyl cellulose. Dry solvents, dry 0. 0440 0. 0573 0. 0000 0. 0268 0. 61 0. 00

washing, 10 minutes reaction time.

B Standard conditions (0.2 g. dry cellulose, 2.0 ml. dry DMSO, 0.3 ml. dry PD, 1.6 m1. dry TEA, 3.2 m1. ethyl chloro formate added over 12 minutes, reaction time 10 minutes, washed with 10x1 5 ml. dry PD and then 3X 15 m1. dry ethanol) are assumed unless specified otherwise.

ECF added over 12 minutes.

ECF added over 3 minutes.

NorE.Abbreviations: BCF, benzyl chloroformate; DMF, dimethyl forrnamlde; DMSO, dimethyl sulphoxide; ECF, ethyl chloroformate; MCF, methyl chloroformate; PCF, phenyl chlorolormate; PD, p-dioxan; TEA, triethylamine.

Reaction of cellulose carbonate with ammonia and of enzyme preparations in a form in which they can be benzylamine used repeatedly and be more stable to heat and other inactivation conditions than the corresponding soluble Cel u Carbonate (P p as in Example 10 enzyme. This process of water insolubilization of enzymes mi reaction time 8-), was mixed and Stirred with 60 can also be used to concentrate the enzymes produced in 0.36 N ammo hYdIOXide at for 3 a fermentation medium, a cellular extract, biological fluid hours. After centrifugation, aliquots of the s p rn n or other aqueous fluids containing these enzymes either were titrated with 0.1 N hydrochloric acid. The centrialone or i admixture i h other compounds, F h

fuged product was washed and dried as in Example V more than one particular enzyme may be attached simuland in analysis Carried out as usual- Elemental analysis 65 taneously to the cellulose derivative (i.e. a cellulose carof the coupled product yielded C=41.6%, H=5.7% and bonate) in the insolubilization.

The nitrogen content corresponds to a mini- Hydrophilic carriers are favored for enzyme insolubilimum cyclic carbonate content of 11.7% compared with zation since they are more effective in enzyme binding and 16.7% based on titration. The total cyclic carbonate the resulting derivatives tend to be more stable. Thus, riboavailablc for reaction, based or in analysis together nuclease and chymotrypsin have been coupled to both with the appropriate calibration curve with dextran Cardiazotised p-aminobenzyl cellulose (Mitz, M.A. and Sumbonate was 37.6%. A similar coupling was carried out maria, L. 1., Nature, 189, 576 [1961]) and to diazotised with benzylamine, and the percentage cyclic carbonate p-aminobenzoyl cellulose (Lilly, M., Money, (1., Hornby,

based on titration was 11.4% compared with 14.7% W. and Crook, E. M., Biochem. J., 95, 45p [1965]). :Rebased on nitrogen content. cently, creatine phosphotransfcrase has been coupled to diazotised p-aminobenzoyl cellulose (Hornby, W. E, Lilly, M. D. and Crook, E. M., Biochem. 1., 107, 669 [1968]) and aminoacylase to diazotised p-aminobenzyl cellulose (Tosa, T., Mori, T., Fuse, N, and Chigata, 1., Enzymelogia, 31, 214 [1966]) Mitz and Summaria (1961 Ice. cit.) also used carboxymethyl cellulose azide to prepare water insoluble derivatives of trypsin, chymotrypsin and ribonuclease. Many other carboxymethyl cellulose based preparations have been reported: trypsin and ribonuclease (Epstein, C. J. and Anfinsen, C. B., J. Biol. Chem., 237, 2175 [1962]), trypsin and chymotrypsin (Takami, T. and .Ando, T., Seikagaku 40, 749 [1968]), chymotrypsin, ribonuclease and ficin (Lilly, M., Money, C., Hornby, W. and Crook, M., Biochem. J., 95, 45p [1965]) and many others.

It is also an object of the present invention to provide active water insoluble enzyme preparations wherein the enzyme is chemically coupled with a cellulose carbonate.

Specifically, the present invention provides water insoluble mouse kidney extract, fl-glucosidase, trypsin, a-arnylase, glucoamylase and mouse liver extracts chemically coupled to a cellulose carbonate.

According to the present invention, there is also provided a process for the preparation of a water insoluble enzyme preparation which comprises reacting the enzyme dissolved or suspended in an aqueous solution with a cellulose carbonate or a diazotized diaminobenzene derivative thereof.

Cellulose carbonate and a method for its preparation is described in our copending application S.N. 98,214, filed Dec. 14, 1970, and above.

A diazotized diaminobenzene derivative of cellulose carbonate and a method for its preparation are described in Example XXVII hereafter.

The aqueous solut ion preferably contains a suitable bulfer such as phosphate or borate in the pH range 2.7 to 11.8 (optimum between 6.5 and 8.5). The temperature may be between C. and 50 C., but preferably below 4 C. and the reaction time may be between 2 minutes and 3 hours. Although not always desirable for maximum retention of enzymic or other biological activity, triethylamine or other tertiary organic bases may replace the inorganic buffers or be added to them in this stage of the proces if required. When the enzymic or biological activity is exhausted the enzyme or other entity containing protein can be removed by selective acid, base or enzymic hydrolysis and the cellulose matrix reused to produce cellulose carbonate. In this sense, it constitutes a regeneratable system of insolubilized enzyme production.

Preparation of cellulose carbonate Preparation I Cellulose (l g., Sigmacell type 38 purchased from Sigma Chemical Co. England) was suspended in liquid dirnethyl sulphoxide (10 ml.), p-dioxan (1.5 ml.) and triethylamine (8 ml.) and stirred at 0 C. for 5 minutes. Ethyl chloroformate (16 ml.) was added dropwise, and stirring continued for minutes. The mixture was then neutralised to pH 7.0 with 6 N HCl. The mixture was suspended in 90% ethanol (400 ml.) at 20 C. using a Waring blender, filtered and the cellulose carbonate washed with 90% ethanol (200 ml.), ethanol (200 ml.), diethyl ether (200 ml.) and dried in vacuo over P 0 at 20 C.

Preparation II Preparation I was scaled up five times except that proportionally more dimethyl sulphoxide (150 ml.) was used to suspend the cellulose and only 400 ml. diethyl ether used for washing the cellulose carbonate.

Preparation III Preparation II was scaled up four times (20 g. cellulose) using only 90% ethanol (1.5 1.), ethanol (2 l.) and diethyl ether (0.5 l.) for washing the cellulose carbonate.

Following is a description by way of example of methods of carrying the invention into effect.

EXAMPLE XVI Coupling of cellulose carbonate with mouse kidney extract Washed mouse kidneys (4 g.) were macerated in a topdrive macerator with 0.1 M citrate buffer pH 4.5 (50 ml.) for 5 minutes. The resulting mixture was then centrifuged at 8,700 g. for 20 minutes and the supernatant taken.

Cellulose carbonate (Preparation I, 200 mg.) was suspended in water (10 ml.) at 4 C., and mouse kidney extract (5 ml.) in 0.05 citrate buffer pH 4.4 added followed by triethylamine (0.2 ml.). After stirring for several hours both this and a control in which cellulose replaced cellulose carbonate were centrifuged. The solids were washed with 0.05 M citrate bufier pH 4.4 (5 ml.) and then M sodium chloride in the same buffer in five alternate sequences followed by three washings with buffer. The final contrifuged products (MKE 1 and control 1) were suspended in 10 ml. 0.05 M citrate buffer pH 4.4. The enzyme activity was assayed by incubating 1 ml. MKE suspension or control 1 with 1 ml. p-nitrophenyl-Z-acetamido- 2-deoxy-fl-D-glucopyranoside (10 mg. in 5 ml. citrate buffer) at 40 C. Reaction was terminated by addition of an equal volume of 0.2 M sodium carbonate, and the CD. of the centrifuged supernatant read at 420 m (M.K.E. 1, 0.206; cellulose control 1, 0.086; substrate control, 0.053). Thus, the enzyme fl-N-acetylglucosaminidase is shown to have been bound to the cellulose.

EMMPLE XVII Coupling of cellulose carbonate with almond B- glucosidase Cellulose carbonate, Preparation I (200 mg.) was suspended in water (10 ml.), and fl-glucosidase (10 mg.) in water (5 ml.) added followed by triethylamine (0.2 ml.). After stirring for 3 hours at 4 C., the solid was filtered off, washed with a solution containing both M sodium chloride and M sucrose and then a solution of 0.005 M acetate bulfer pH 4.95 five times alternately, followed by the acetate bulfer twice before being suspended in 0.005 M acetate buffer pH 4.95 (10 ml.). The product (B.G. 1), and cellulose control 2 carried through the same procedure, were separately assayed by incubating 1 ml. suspension with 1 ml. o-nitrophenyl-;3-D-glucopyranoside (0.1076 g. in 10 ml. acetate buffer) at 37 C. The reaction was terminated as in Example XVI after 3.5 hours and the CD. of each centrifuged supernatant read at 420 m z (B.G. 1, 2.235; cellulose control 2, 0.417; substrate control, 0.130).

In a repeat experiment but effecting the coupling with fl-glucosidase at 0 C. and maintaining a 20 minute stirring period for each washing also at 0 C. the second batch B6. 2 when assayed showed OD. 420 m 0.761; cellulose control 3, 0.117; substrate control, 0.024; after a 1-hour incubation at 36 C. instead of 3.5 hours as previously.

EXAMPLE XVIII Coupling of cellulose carbonate with trypsin Cellulose carbonate, Preparation II in 200 mg. aliquots, was suspended in water (10 ml.), and coupled with trypsin (0.0261 g.) in 10 ml. water (a) without addition of triethylamine (b) with addition of 20 ,ul. triethylamine and (c) with addition of 200 pl. triethylamine. A control experiment was performed in which the conditions of (b) were used except for the replacement of cellulose carbonate by cellulose (200 mg.). After stirring at 4 C. for 3 hours, the normal procedure of washing was followed as in Example XVII but using 0.05 M phosphate pH 8.0 instead of acetate. Each product was finally suspended in 0.5 M phosphate buffer pH 8.0 (10 ml.) and an aliquot (0.5 ml.) assayed by using N-a-benzoyl-L-arginine ethyl ester hydrochloride as substrate (0.5 ml.; 0.0795 g. in

EXAMPLE XIX Optimum pH for coupling B-glucosidase to cellulose carbonate in the presence of organic acids or bases Varying amounts of base (triethylamine) or acid (glacial acetic acid) were added to constant volumes (10 ml.) of fl-glucosidase (1 mg.) in aqueous solution. The pH of each was recorded before and after the addition of cellulose carbonate, Preparation III (200 mg.), to each solution at 4 C. using the otherwise normal procedure (see Example XVII) for coupling the enzyme to cellulose carbonate and subsequent washing procedure using 0.005 M acetate buffer pH 4.95. Enzyme activity was assayed as in Example XVII.

. Resultant Glacial pH enzyme acacetic tivity, O.D. acid, pl- Before Atter 420 nm.

Trlethylamine, u 1.:

The corresponding substrate blank had OD. 420 nm. 0.008.

EXAMPLE XX Optimum pH for coupling p-glucosidase to cellulose carbonate in the absence of triethylamine pH of buffer in coupling Enzyme activity-0D. 420 nm. 6. 7. 05 8. 10 9. 00 9. 90

On cellulose carbonate 0. 712 1. 132 1. 323 0. 628 0. 387 On cellulose 0. 141 0. 160 0. 164 0. 106 1 0. 106

The corresponding substrate blank had OD. 420 nm. 0.013.

EXAMPLE XXI Heat stability of insolubilized p-glucosidase Aliquots (0.5 ml.) of cellulose carbonate insolubilized ,B-glucosidase (Example XX, pH 8.1) and soluble fl-glucosidase of the same order of activity were incubated at 37 C. and assayed at various times for retention of activity as in Example II; both soluble and insolubilized enzyme were in 0.005 M acetate buffer pH 4.95, but the incubation time for enzyme assay with respect to o-nitrophenyl p-D-glucopyranoside as substrate was minutes throughout. Substrate controls were incubated simultaneously and individual assays have been corrected.

Time

0 7 1 2 3 4 6 111'. hr. day days days days days Percent activity retention:

Insoluble enzyme- 93 87 74 47 38 33 Soluble enzyme 100 17 11 5 3 1 1 EXAMPLE XXII pH stability of insolubilized fi-glucosidase Aliquots (1 ml.) of cellulose carbonate insolubilized 8-glucosidase (Example XX, pH 7.05) were centrifuged, resuspended in bulfer (2 ml.) of diifering pH and incubated for 1 day at 37 C. before being again centrifuged, washed with acetate bulfer pH 5.0, recentrifuged and resuspended in 0.005 M acetate buffer pH 4.95 (1 ml.). Each aliquot was assayed as in Example XXI.

pH: OD. 420 nm. 2.2 0.018 3.5 0.04 5

untreated cellulose carbonate insolubilized B-glucosidase gave OD. 420 nm. 0.428.

EXAMPLE XXIH pH-activity relationships of free and bound (cellulose carbonate) ,3 glucosidase with o nitrophenyl ,B D- glucopyranoside as substrate then added to an equal volume of 0.2 M sodium carbonate solution and the optical density at 420 nm. read.

(b) Bound enzyme.--The cellulose carbonate-enzyme (20 mg. suspended per ml.) was stirred in the presence of the substrate (final concentration, 1 mg./ml.) in the appropriate buffered solutions (see below) for 30 minutes at 37 C. and assayed at various times for retenwas added to an equal volume of 0.2 M sodium carbonate and the optical density read at 420 nm.

The results are shown in Table II.

TABLE II Activity of free and bound (cellulose carbonate) fl-glucosldase against o-nitrophenyl-fl-D-g1ucopyranoside 0.D. at 420 nm.

Free Bound pH Bnfler (final concentration) enzyme enzyme 3. 0. 024 0. 119 4. 0. 198 0.322 5. 0. 441 0. 540 6. 0. 429 0. 388 7. 0. 202 0. 217 8. 0 0. 0.108 9. Boric acidborax (0.05 M) 0.070 0.098 10.0- Borax-sodium hydroxide (0.05 M) 0. 024 0. 062

EXAMPLE XXIV Coupling of mouse liver extract enzymes to cellulose carbonate Mouse liver' extract was prepared using the method for mouse kidney extract described in Example XVI.

Cellulose carbonate (200 mg.) in water (10 ml.) was stirred with mouse liver extract (10 ml.) in 0.05 M citrate pH 4.4 and 0.2 ml. triethylamine added. After leaving overnight the product was washed with six alternate sequences of 0.05 M citrate buffer pH 4.4 and 1 M sodium 11 12 chloride. A control experiment in which cellulose was preparation caused release of 35 ,ug. of glucose while the substituted for cellulose carbonate was also carried out. control preparation caused release of 17,ug. The insolubilized enzyme activities were determined on EXAMPLE XXVH 1 ml. aliquots of the suspensions of both final products in 10 ml. 0.05 M citrate buffer pH 4.4 by incubating Coupling of B-glucosidase with adiazotized diaminowith the substrates (1 ml., 25 mg. in 10 ml. bulfer) shown belllenfi d at v f C ll l s carbonate in Table III alongside substrate controls and reading at Diazotized diaminobenzene derivative m Diaminm 420 The effect P the Substrates llsted at P benzene (distilled in vacuo) was dissolved in a mixture of Table II show there has been reacted mouse liver ;3- f dimethylformamide (100 1 1,), ater (100 mL) and galactosidase, a-mannosidase, a-glucosidase, and B-N- triethylamine (2.5 ml.). Cellulose carbonate (500 mg.) acetylglucosaminidase. was added slowly to the stirred solution. The mixture TABLE TIL-ENZYMATIC ACTIVITY OF INSOLUBILIZED MOUSE LIVER EXTRACT ENZYMES Substrate p-Nitrophenyl o-Nitrophenyl p-Nitrophenyl p-Nitrophenyl 2-acetamido p-D-galactoa-D-niannoa-D-gluco- 2-deoxy 13-D- pyranoside pyranoside pyranoside glucopyranoside Incubation time 2.5 hr. at 37 C. 2.5 hr. at 40 C. 2.5 hr. at 37 C. 2.5 hr. at 37 C.

Cellulose carbonate-mouse liver extract condensate-.- 0. 109 0. 135 0.321 0.370 Cellulose-mouse liver extract control 0. 030 Zero Zero 0. 032

EXAMPLE XXV was stirred overnight at room temperature and then fil- Optimum pH for coupling a-amylase to cellulose 2 583 5 g gg gis 2 2 22: g g ga gi g fig fi h r' l in carbonate m abs ence of t lethy am e 25 ter (200 ml.), and then it was dried in vacuo over P 0 M'Amylase was f p 118mg the Procedure of P A sample of this material (100 mg.) was stirred at 0 X at concentraflon 20 P 100 681101036 C. in N hydrochloric acid solution (5.0 ml.), sodium nibonate (Preparation 118mg q s fi s without trite solution (2%, 5.0 ml.) was added slowly and the ethylamine pH 4.5-10.0 with 3 hours coupling at 4 C- mixture stirred at 0 C. for 15 minutes. The solid was in appropriate buflers. then recovered by centrifugation and washed three times by stirring for 15 minutes with 0.1 M phosphate buffer Bound g g g pH 7.8 10 ml.). rotein, per mg, Per Coupling of fl-glucosidase.-The solid prepared as PH mg-g-solid Pmtein wtmtion above was stirred with fl-glucosidase solution (5 mg. in 3,5 4 8 0.1 M phosphate buffer, pH 7.8; 20 ml.) at 5 C. for 18 if ggg hours. An ice-cold saturated solution of B-naphthol in 414 21,9 1s saturated sodium acetate solution (5 ml.) was added and 2:5 3 fgg the mixture stirred for 15 minutes. The solid was then 4O recovered by centrifugation and washed twice as described above. A control preparation was prepared in exactly the same way using cellulose in place of the diazotized diaminobenzene derivative of cellulose carbonate. Both were made up to 5 ml. with 0.05 M acetate buifer pH 5.0.

Assay of B-glucosidase activity.This was carried out in the normal manner. The test preparation liberated 1.06 ,umole of O-nitrophenol in 15 minutes at 37 C. while the control liberated 0.05 ,umole.

1 unit of (it-amylase is that which liberates reducing sugar equivalent to 1 mg. maltose in 3 minutes at 20 C. Activity of free enzyme in solution=16 units/mg. protein.

a-Amylase was also applied at concentration 20 mg. per 100 mg. cellulose carbonate (Preparation II) at pH 7.6 for coupling times 0.5, 1, 3 and 24 hours.

Bound Enzyme Percent Coupling time protein units retention A L XX III i; 5}; 23:2 Coupling of glucoamylase with diazotized diamino- 5.; 2g 3. benzene derivative of cellulose carbonate l The diazotized diaminobenzene derivative (100 mg.)

EXAMPLE XXVI was prepared as described in Example XXYII. Glucoamylase solution (1.0 ml.) was coupled to this derivative Coupling of slucoamylase to cellulose carbonate as described in Example XXVII. The same washing procellulose carbonate (100 mg) was Stirred with a So1u cedure was carried out and the solid product was finally tion of glucoamylase (ex. Aspergillus niger, 27 units per Suspended 02 M acetate ffer pH 4-0 (5 ml.). A conmg. protein, mg. protein per ml. in M Phosphate trol experiment was carried out in which cellulose rebuffer pH 7.8; 1.0 ml.) at4 C. for 3 hours. The solid Placed the qenvatlvewas filtered off, washed as described in Example XVII The enzymic activities of the test and control preparaand finally suspended in 0.2 M acetate buffer pH 4.0 (5 P were assayed descnbed Example XXVI- 3 ml.). A control reaction was carried out in the same way Sohd phifse enzyme hbifrated 69 of glucose Per 1111- m using 1.0 ml. of glucoamylase solution and 100 mg. cel- 1 Wh1 1e control hberated 23 l' What is claimed is:

1. A process for the preparation of a water insoluble enzyme preparation which process comprises reacting an Starch solution (1% in 0.2 M acetate buffer pH 4.0; enzyme selected from the group consisting of fi-N-acetyl- 4.5 ml.) was incubated, with stirring with the suspension 70 glucosaminidase, fl-glucosidase, trypsin, tit-amylase, gluco- Assay for glucoarnylase activity of the solid phase enzyme (0.5 ml.) for 1 hour at 45 C. amylase, ,G-galactosidase, a-mannosidase and a-glucosidase The assay mixture Was then cooled and centrifuged and dissolved or suspended in an aqueous solution with a cel- 0.1 ml. of the supernatant taken for glucose determinalulose carbonate comprising trans-cyclic carbonate grouption in the glucose oxidase assay for which a standard ings bridging C and C of some or all of its 1,4-BD-glureference curve was established. The solid phase enzyme copyranose units.

2. A process as claimed in claim 1, wherein the enzyme is mouse kidney fi-N-acetylglucosaminidase, mouse liver S-galactosidase, mouse liver a-mannosidase, mouse liver a-glucosidase or mouse liver fi-N-acetylglucosaminidase.

3. A process as claimed in claim 1, wherein the aqueous solution is in the pH range of 2.7 to 11.8.

4. A process as claimed in claim 3, wherein the pH range is from 6.5 to 8.5.

5. A process as claimed in claim 3; wherein the temperature is between C. and 50 C. and the reaction time between 2 minutes and 3 hours.

6. Active water insoluble enzyme preparations wherein an enzyme selected from the group consisting of p-N-acetylucosaminidase, B-glucosidase, trypsin, a-amylase, glucoamylase, fl-galactosidase, u-mannosidase and a-glucosidase is chemically coupled to a cellulose carbonate comprising trans-cyclic carbonate groups bridging C and C of some or 'all of its 1,4-;3D-glucopyranose units.

7. Water insoluble mouse kidney fl-N-acetylglucosamidase chemically coupled to a cellulose carbonate comprising trans-cyclic carbonate groupings bridging C and C of some or all of its 1,4-flD-glucopyranose units.

8. Water insoluble mouse liver B-galactosidase, mouse liver a-mannosidase, mouse liver a-glucosidase or mouse liver B-N-acetylglucosaminidase chemically coupled to a cellulose carbonate comprising trans-cyclic carbonate groupings bridging C and C of some or all of its 1,4-,8D- glucopyranose units.

9. Water insoluble B-glucosidase chemically coupled to a cellulose carbonate comprising trans-cyclic carbonate groupings bridging C and C of some or all of its 1,4-pD- glucopyranose units.

10. Water insoluble trypsin chemically coupled to a cellulose carbonate comprising trans-cyclic carbonate groupings bridging C; and C of some or all of its 1,4-,BD- glucopyranose units. 1

11. Water insoluble a-amylase chemically coupled to cellulose carbonate comprising trans-cyclic carbonate groupings bridging C and C of some or all of its 1,4-fiD- glucopyranose unitsf 12. Water insoluble glucoamylase chemically coupled to a cellulose carbonate comprising trans-cyclic carbonate groupings bridging C and C of some or all of its 1,4-pD- glucopyranose units.

References Cited UNITED STATES PATENTS 3,419,543 12/1968 Mold et al 260-228 X 3,616,229 10/ 1971 Wildi et a1. -68 3,627,638 12/1971 Barker et a1. 195-63 3,167,485 1/1965 Katchalski et al 195-63 OTHER REFERENCES I Weliky, et al., The Chemistry and Use of Cellulose Derivatives for the Study of Biological Systems, Immunochemistry, December 1965, vol. 2 (pp. 302-312).

Noller, C. R., Chemistry of Organic Compounds, W. B. Saunders Co., Philadelphia, 1951 (pp. 238-240).

DAVID M. NAFF, Primary Examiner US. Cl. X.Rl. 195-68, Dig. 11 

